Model legs in Maya
In this tutorial, we continue to build our model by fleshing out the legs
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We continue our introduction to modeling in Maya by building up the legs. Before tackling the legs in CG, I first examine the reference, looking at how the underlying bones and muscles affect the skin. By understanding this structure and flow, we can start to transfer them to the model, making the edges mimic the natural rhythms that occur. We don't need to add every single muscle but we can think about the muscle masses and bony areas: the quadriceps, the calf muscles and the bony regions of the ankles, for example. By doing so, we can create the creases and bulges that should occur during deformation as well as hinting at an underlying structure existing within the hollow model.
For this tutorial, we will continue to use the reference from the awesome folks at 3dscanstore. However, please note, as well as looking at the front, side and back views supplied, I have also used all the other images that come with the collection to extract as much info as I can during the modeling process. Check out what they have to offer; it's all good stuff.
Obviously this tutorial is aimed primarily at new Maya users, familiarizing readers with one way to skin the modeling cat. However, there are many ways to skin this particular cat, and I urge you to explore and experiment with other packages and processes to see what suits you best.
Step 1: Plan ahead
Okay, so the first thing I like to do is to analyze the reference. I've taken some images into Photoshop and produced a quick draw-over indicating the forms I want to capture and the directions in which my edges should flow to achieve the desired results. Muscle masses that I have highlighted include: the quadriceps, the calf muscle, the Sartorius and the tensor fasciae latae. I also want to indicate the popliteal fossa (the knee pit), the Achilles tendon, the patella, the shaft of the tibia and the medial and lateral malleoli (inner and outer ankle bones). You could, if you wanted, take this into Maya, pop it on to an image plane and use the lines to determine where you make your cuts on the model.
Step 2: Extract the leg
The first thing we need to do in Maya is extract the leg from the rest of the geometry. To do this, go into Face mode (F11) and select all the faces you wish to separate from the mesh. With the faces selected, hit F3 to be in the Polygons module and go Mesh > Extract. Go back into Object mode (F8), select all the geometry in the scene and go Edit > Delete by Type > History. In the Outliner, you may notice some of the geometry parented under group nodes. Simply un-parent them from the groups by selecting them and going Edit > Unparent or hitting Shift+P. You can then delete the groups. To tidy up the viewport a little, create some layers and add the geometry parts that we do not need to view at the moment. You can then show and hide them easily as well as reference them.
Step 3: Smoothing and pushing the basic forms
Once I have my leg separated, I first go to Mesh > Smooth to give me more points to push about. At this early stage, I am already thinking about where the patella will emerge from and how to define the ridge of the tibia that sits just below the flesh. Once I have pushed the vertices as much as possible, I use the Split Polygon Tool to start defining the edge flow. To access the Split Polygon Tool (hidden from the menu) hold Shift+RMB over the model and go Split > Split Polygon Tool. Beginning with the Sartorius, I make a deep cut from the anterior superior iliac spine towards the inside of the knee and continue to carry it through to the ankle (in reality, the muscle inserts into a tendon on the inside of the knee).
Step 4: Extruding out the masses
Continuing to bring out the major masses, I select a series of faces and then use Edit Mesh > Extrude to pull them out before working back into the model. I do this for the quadriceps and the patella. I'm not looking to create Mr. Universe here so I'm always softening the muscles back into the geometry but defining one or two edges to highlight the existence of the muscle. You may be thinking: Why add the flow if we won't really be able to see it? The reason for doing so is that if I need to animate the leg and show tension, the topology will be there and will support me to do so. To soften the muscle masses back into the form, I go Mesh > Sculpt Geometry Tool with the Operation set to Relax. By painting over the geometry, you can even out the edges.
Step 5: Adding further muscle masses
At this stage, I am still only adding as much detail needed to bring the forms out. Going in too heavily will mean you have lots of points to push and pull and can make things more complicated than they need to be. Work on the major forms and edges first and then you can always up the resolution. I continued to work on the lower leg by extruding out faces to act as the tibialis anterior, which is the muscle at the front of your lower leg that you'll notice in action when you lift your toes up (dorsiflexion). Again, during deformation, indicating that this muscle lives below the surface will add extra believability to your work. Continuing to work round to the back of the lower leg, indicate the calf muscles and notice how one of the heads of the gastrocnemius muscle sits higher than the other. Whist working on the back of the lower leg, you can also bring out the Achilles tendon by bringing the edges tighter together at the back of the ankle.
Step 6: The knee pit and the bottom
Working back up the leg, we can push in some edges to create the knee pit or popliteal fossa as it's known anatomically. Inserting into the knee region, we would have the hamstring muscles. I've decided not to define them as strongly as we did the quadriceps as I felt I had enough detail there to push the form during deformation. Should you feel you want to, feel free to further accentuate the region. That will bring us to the gluteus maximus, the defining muscle of man according to Aristotle. For this mass of muscle, I again selected a series of faces and performed an extrusion. This allowed me to have enough detail to create a buttock crease, which is especially useful if modeling builders.
Step 7: Bringing it all together
As we've built the leg independently of the torso, we'll need to do some clean-up work to bring the two together. First, select both pieces of geometry and go Mesh > Combine. Next, use the Merge Vertex Tool to drag and drop one vertex onto another to connect the leg to the torso. You'll notice that you'll need some extra edge loops to have the meshes combine cleanly. I had to add extra edge loops through the side of the torso to give me enough points to connect the leg to. Once the two parts are combined and the seams closed, you will still need to go in and push the forms to tidy them up. At this stage, use a combination of the Sculpt Geometry Tool and Soft-Selection (press B to enable and disable) to move the points around. As you go through the clean-up phase, try to keep the face sizes relatively square where possible. Don't worry too much if it's not doable yet as we will be coming back to refine the entire model when all the elements are complete. Next time, we'll add the arms.
Top tip: Check deformation early
As I model, I like to test out the deformation to see if the geometry will hold up. To do this, I go to the Animation module by hitting F2. Go Skeleton > Joint Tool. In an orthographic view, usually Front or Side, I will create a joint chain. I'll then position the joints into place, checking from every angle that they sit within the model. Then select the root joint, the geometry and go Skin > Bind Skin > Smooth Bind. You can now rotate the joints and the geometry should follow. Spend a few minutes refining the weighting by selecting the model and going Skin > Edit Smooth Skin > Paint Skin Weights Tool and then test out the deformation once more.
Please note that when creating the joints to be used for an animation rig, I would place the joints with much more care and make sure all rotations are zeroed out in the default pose. As we are just testing, I'm working more loosely.
Click HERE to see the previous tutorial in this series.
Want to start from the beginning? Click HERE to see the first tutorial in this series.
To see more by Jahirul Amin, check out Beginner's Guide to Character Creation in Maya
and 3ds Max Projects